
/* Copyright (c) Mark J. Kilgard, 1994. */

/*
 * (c) Copyright 1993, Silicon Graphics, Inc.
 * ALL RIGHTS RESERVED
 * Permission to use, copy, modify, and distribute this software for
 * any purpose and without fee is hereby granted, provided that the above
 * copyright notice appear in all copies and that both the copyright notice
 * and this permission notice appear in supporting documentation, and that
 * the name of Silicon Graphics, Inc. not be used in advertising
 * or publicity pertaining to distribution of the software without specific,
 * written prior permission.
 *
 * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
 * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
 * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
 * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
 * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
 * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
 * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
 * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN
 * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
 * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * US Government Users Restricted Rights
 * Use, duplication, or disclosure by the Government is subject to
 * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
 * (c)(1)(ii) of the Rights in Technical Data and Computer Software
 * clause at DFARS 252.227-7013 and/or in similar or successor
 * clauses in the FAR or the DOD or NASA FAR Supplement.
 * Unpublished-- rights reserved under the copyright laws of the
 * United States.  Contractor/manufacturer is Silicon Graphics,
 * Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311.
 *
 * OpenGL(TM) is a trademark of Silicon Graphics, Inc.
 */
/*  texturesurf.c
 *  This program uses evaluators to generate a curved
 *  surface and automatically generated texture coordinates.
 */

#include <stdlib.h>
#include <GL/glut.h>
#include <math.h>

GLfloat ctrlpoints[4][4][3] = {
    {{ -1.5, -1.5, 4.0}, { -0.5, -1.5, 2.0},
	{0.5, -1.5, -1.0}, {1.5, -1.5, 2.0}},
    {{ -1.5, -0.5, 1.0}, { -0.5, -0.5, 3.0},
	{0.5, -0.5, 0.0}, {1.5, -0.5, -1.0}},
    {{ -1.5, 0.5, 4.0}, { -0.5, 0.5, 0.0},
	{0.5, 0.5, 3.0}, {1.5, 0.5, 4.0}},
    {{ -1.5, 1.5, -2.0}, { -0.5, 1.5, -2.0},
	{0.5, 1.5, 0.0}, {1.5, 1.5, -1.0}}
};

GLfloat texpts[2][2][2] = {{{0.0, 0.0}, {0.0, 1.0}},
			{{1.0, 0.0}, {1.0, 1.0}}};

static void display(void)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glColor3f(1.0, 1.0, 1.0);
    glEvalMesh2(GL_FILL, 0, 20, 0, 20);
    glFlush();
}

#define	imageWidth 64
#define	imageHeight 64
GLubyte image[3*imageWidth*imageHeight];

static void makeImage(void)
{
    int i, j;
    float ti, tj;

    for (i = 0; i < imageWidth; i++) {
	ti = 2.0*3.14159265*i/imageWidth;
	for (j = 0; j < imageHeight; j++) {
	    tj = 2.0*3.14159265*j/imageHeight;

	    image[3*(imageHeight*i+j)] = (GLubyte) 127*(1.0+sin(ti));
	    image[3*(imageHeight*i+j)+1] = (GLubyte) 127*(1.0+cos(2*tj));
	    image[3*(imageHeight*i+j)+2] = (GLubyte) 127*(1.0+cos(ti+tj));
	}
    }
}

static void myinit(void)
{
    glMap2f(GL_MAP2_VERTEX_3, 0, 1, 3, 4,
	    0, 1, 12, 4, &ctrlpoints[0][0][0]);
    glMap2f(GL_MAP2_TEXTURE_COORD_2, 0, 1, 2, 2,
	    0, 1, 4, 2, &texpts[0][0][0]);
    glEnable(GL_MAP2_TEXTURE_COORD_2);
    glEnable(GL_MAP2_VERTEX_3);
    glMapGrid2f(20, 0.0, 1.0, 20, 0.0, 1.0);
    makeImage();
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexImage2D(GL_TEXTURE_2D, 0, 3, imageWidth, imageHeight, 0,
		 GL_RGB, GL_UNSIGNED_BYTE, image);
    glEnable(GL_TEXTURE_2D);
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_NORMALIZE);
    glShadeModel (GL_FLAT);
}

static void myReshape(int w, int h)
{
    glViewport(0, 0, w, h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    if (w <= h)
	glOrtho(-4.0, 4.0, -4.0*(GLfloat)h/(GLfloat)w,
	    4.0*(GLfloat)h/(GLfloat)w, -4.0, 4.0);
    else
	glOrtho(-4.0*(GLfloat)w/(GLfloat)h,
	    4.0*(GLfloat)w/(GLfloat)h, -4.0, 4.0, -4.0, 4.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glRotatef(85.0, 1.0, 1.0, 1.0);
}

static void
key(unsigned char k, int x, int y)
{
  switch (k) {
  case 27:  /* Escape */
    exit(0);
    break;
  default:
    return;
  }
  glutPostRedisplay();
}

int main(int argc, char** argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
    glutCreateWindow (argv[0]);
    myinit();
    glutReshapeFunc (myReshape);
    glutDisplayFunc(display);
    glutKeyboardFunc(key);
    glutMainLoop();
    return 0;             /* ANSI C requires main to return int. */
}
